Super tempted by that MS "deal", $9 is hard to say no to, but what if MS never bother to update it? Are the settings the same as the Steam one, besides exclusive fullscreen?

I think it will be unlikely for them to not bother to update the game, isn't it down to the developers to push out the updates? It could be possible that they've already pushed out the updates but it could be going through a verification process, much like how Xbox Live and PlayStation Network handle game updates.

If they don't bother to update the Windows 10 version its not going to go down well for Microsoft or the developers.

PC Gamers will just prefer to use Steam instead of the Windows 10 store if it means that their games won't be able to get the latest updates in a reasonable amount of time like Steam does.